/*!	 mod_gradient/radialgradient.cpp
**	 Implementation of the "Radial Gradient" layer
**
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**	Copyright (c) 2007 Chris Moore
**	Copyright (c) 2011-2013 Carlos López
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
*/

#ifdef USING_PCH
#	include "pch.h"
#else
#ifdef HAVE_CONFIG_H
#	include <config.h>
#endif

#include <synfig/localization.h>
#include <synfig/general.h>

#include <synfig/string.h>
#include <synfig/time.h>
#include <synfig/context.h>
#include <synfig/paramdesc.h>
#include <synfig/renddesc.h>
#include <synfig/surface.h>
#include <synfig/value.h>
#include <synfig/valuenode.h>

#include "radialgradient.h"

#endif

using namespace etl;
using namespace std;
using namespace synfig;

SYNFIG_LAYER_INIT(RadialGradient);
SYNFIG_LAYER_SET_NAME(RadialGradient, "radial_gradient");
SYNFIG_LAYER_SET_LOCAL_NAME(RadialGradient, N_("Radial Gradient"));
SYNFIG_LAYER_SET_CATEGORY(RadialGradient, N_("Gradients"));
SYNFIG_LAYER_SET_VERSION(RadialGradient, "0.1");
SYNFIG_LAYER_SET_CVS_ID(RadialGradient, "$Id$");

RadialGradient::RadialGradient():
    Layer_Composite(1.0, Color::BLEND_COMPOSITE),
    param_gradient(ValueBase(Gradient(Color::black(), Color::white()))),
    param_center(ValueBase(Point(0, 0))),
    param_radius(ValueBase(Real(0.5))),
    param_loop(ValueBase(false)),
    param_zigzag(ValueBase(false))
{
    SET_INTERPOLATION_DEFAULTS();
    SET_STATIC_DEFAULTS();
}

bool
RadialGradient::set_param(const String & param, const ValueBase &value)
{
    IMPORT_VALUE(param_gradient);
    IMPORT_VALUE(param_center);
    IMPORT_VALUE(param_radius);
    IMPORT_VALUE(param_loop);
    IMPORT_VALUE(param_zigzag);

    return Layer_Composite::set_param(param, value);
}

ValueBase
RadialGradient::get_param(const String &param)const
{
    EXPORT_VALUE(param_gradient);
    EXPORT_VALUE(param_center);
    EXPORT_VALUE(param_radius);
    EXPORT_VALUE(param_loop);
    EXPORT_VALUE(param_zigzag);

    EXPORT_NAME();
    EXPORT_VERSION();

    return Layer_Composite::get_param(param);
}

Layer::Vocab
RadialGradient::get_param_vocab()const
{
    Layer::Vocab ret(Layer_Composite::get_param_vocab());

    ret.push_back(ParamDesc("gradient")
                  .set_local_name(_("Gradient"))
                  .set_description(_("Gradient to apply"))
                 );

    ret.push_back(ParamDesc("center")
                  .set_local_name(_("Center"))
                  .set_description(_("Center of the gradient"))
                 );

    ret.push_back(ParamDesc("radius")
                  .set_local_name(_("Radius"))
                  .set_description(_("This is the radius of the circle"))
                  .set_is_distance()
                  .set_origin("center")
                 );

    ret.push_back(ParamDesc("loop")
                  .set_local_name(_("Loop"))
                  .set_description(_("When checked the gradient is looped"))
                 );

    ret.push_back(ParamDesc("zigzag")
                  .set_local_name(_("ZigZag"))
                  .set_description(_("When checked the gradient is symmetrical at the center"))
                 );

    return ret;
}

inline Color
RadialGradient::color_func(const Point &point, float supersample)const
{
    Gradient gradient = param_gradient.get(Gradient());
    Point center = param_center.get(Point());
    Real radius = param_radius.get(Real());
    bool loop = param_loop.get(bool());
    bool zigzag = param_zigzag.get(bool());

    Real dist((point - center).mag() / radius);

    if (loop) {
        dist -= floor(dist);
    }

    if (zigzag) {
        dist *= 2.0;
        supersample *= 2.0;

        if (dist > 1) {
            dist = 2.0 - dist;
        }
    }

    if (loop) {
        if (dist + supersample * 0.5 > 1.0) {
            float  left(supersample * 0.5 - (dist - 1.0));
            float right(supersample * 0.5 + (dist - 1.0));
            Color pool(gradient(1.0 - (left * 0.5), left).premult_alpha()*left / supersample);

            if (zigzag) {
                pool += gradient(1.0 - right * 0.5, right).premult_alpha() * right / supersample;
            } else {
                pool += gradient(right * 0.5, right).premult_alpha() * right / supersample;
            }

            return pool.demult_alpha();
        }

        if (dist - supersample * 0.5 < 0.0) {
            float  left(supersample * 0.5 - dist);
            float right(supersample * 0.5 + dist);
            Color pool(gradient(right * 0.5, right).premult_alpha()*right / supersample);

            if (zigzag) {
                pool += gradient(left * 0.5, left).premult_alpha() * left / supersample;
            } else {
                pool += gradient(1.0 - left * 0.5, left).premult_alpha() * left / supersample;
            }

            return pool.demult_alpha();
        }
    }

    return gradient(dist, supersample);
}

float
RadialGradient::calc_supersample(const synfig::Point &/*x*/, float pw, float /*ph*/)const
{
    Real radius = param_radius.get(Real());
    return 1.2 * pw / radius;
}

synfig::Layer::Handle
RadialGradient::hit_check(synfig::Context context, const synfig::Point &point)const
{
    if (get_blend_method() == Color::BLEND_STRAIGHT && get_amount() >= 0.5) {
        return const_cast<RadialGradient*>(this);
    }

    if (get_amount() == 0.0) {
        return context.hit_check(point);
    }

    if ((get_blend_method() == Color::BLEND_STRAIGHT || get_blend_method() == Color::BLEND_COMPOSITE) && color_func(point).get_a() > 0.5) {
        return const_cast<RadialGradient*>(this);
    }

    return context.hit_check(point);
}

Color
RadialGradient::get_color(Context context, const Point &pos)const
{
    const Color color(color_func(pos));

    if (get_amount() == 1.0 && get_blend_method() == Color::BLEND_STRAIGHT) {
        return color;
    } else {
        return Color::blend(color, context.get_color(pos), get_amount(), get_blend_method());
    }
}

bool
RadialGradient::accelerated_render(Context context, Surface *surface, int quality, const RendDesc &renddesc, ProgressCallback *cb)const
{
    RENDER_TRANSFORMED_IF_NEED(__FILE__, __LINE__)

    SuperCallback supercb(cb, 0, 9500, 10000);

    if (get_amount() == 1.0 && get_blend_method() == Color::BLEND_STRAIGHT) {
        surface->set_wh(renddesc.get_w(), renddesc.get_h());
    } else {
        if (!context.accelerated_render(surface, quality, renddesc, &supercb)) {
            return false;
        }

        if (get_amount() == 0) {
            return true;
        }
    }

    int x, y;

    Surface::pen pen(surface->begin());
    const Real pw(renddesc.get_pw()), ph(renddesc.get_ph());
    Point pos;
    Point tl(renddesc.get_tl());
    const int w(surface->get_w());
    const int h(surface->get_h());

    if (get_amount() == 1.0 && get_blend_method() == Color::BLEND_STRAIGHT) {
        for (y = 0, pos[1] = tl[1]; y < h; y++, pen.inc_y(), pen.dec_x(x), pos[1] += ph)
            for (x = 0, pos[0] = tl[0]; x < w; x++, pen.inc_x(), pos[0] += pw) {
                pen.put_value(color_func(pos, calc_supersample(pos, pw, ph)));
            }
    } else {
        for (y = 0, pos[1] = tl[1]; y < h; y++, pen.inc_y(), pen.dec_x(x), pos[1] += ph)
            for (x = 0, pos[0] = tl[0]; x < w; x++, pen.inc_x(), pos[0] += pw) {
                pen.put_value(Color::blend(color_func(pos, calc_supersample(pos, pw, ph)), pen.get_value(), get_amount(), get_blend_method()));
            }
    }

    // Mark our progress as finished
    if (cb && !cb->amount_complete(10000, 10000)) {
        return false;
    }

    return true;
}

bool
RadialGradient::accelerated_cairorender(Context context, cairo_t *cr, int quality, const RendDesc &renddesc, ProgressCallback *cb)const
{
    Gradient gradient = param_gradient.get(Gradient());
    Point center = param_center.get(Point());
    Real radius = param_radius.get(Real());
    bool loop = param_loop.get(bool());

    cairo_save(cr);
    cairo_pattern_t* pattern = cairo_pattern_create_radial(center[0], center[1], 0.0, center[0], center[1], radius);
    bool cpoints_all_opaque = compile_gradient(pattern, gradient);

    if (loop) {
        cairo_pattern_set_extend(pattern, CAIRO_EXTEND_REPEAT);
    }

    if (quality > 8) {
        cairo_pattern_set_filter(pattern, CAIRO_FILTER_FAST);
    } else if (quality >= 4) {
        cairo_pattern_set_filter(pattern, CAIRO_FILTER_GOOD);
    } else {
        cairo_pattern_set_filter(pattern, CAIRO_FILTER_BEST);
    }

    if (
        !
        (is_solid_color() ||
         (cpoints_all_opaque && get_blend_method() == Color::BLEND_COMPOSITE && get_amount() == 1.f))
    ) {
        // Initially render what's behind us
        if (!context.accelerated_cairorender(cr, quality, renddesc, cb)) {
            if (cb) {
                cb->error(strprintf(__FILE__"%d: Accelerated Cairo Renderer Failure", __LINE__));
            }

            return false;
        }
    }

    cairo_set_source(cr, pattern);
    cairo_paint_with_alpha_operator(cr, get_amount(), get_blend_method());

    cairo_pattern_destroy(pattern); // Not needed more
    cairo_restore(cr);
    return true;
}

bool
RadialGradient::compile_gradient(cairo_pattern_t* pattern, Gradient mygradient)const
{
    bool zigzag = param_zigzag.get(bool());
    bool loop = param_loop.get(bool());

    bool cpoints_all_opaque = true;
    float a, r, g, b;
    Gradient::CPoint cp;
    Gradient::const_iterator iter;
    mygradient.sort();

    if (zigzag) {
        Gradient zgradient;

        for (iter = mygradient.begin(); iter != mygradient.end(); iter++) {
            cp = *iter;
            cp.pos = cp.pos / 2;
            zgradient.push_back(cp);
        }

        for (iter = mygradient.begin(); iter != mygradient.end(); iter++) {
            cp = *iter;
            cp.pos = 1.0 - cp.pos / 2;
            zgradient.push_back(cp);
        }

        mygradient = zgradient;
    }

    mygradient.sort();

    if (loop) {
        cp = *mygradient.begin();
        a = cp.color.get_a();
        r = cp.color.get_r();
        g = cp.color.get_g();
        b = cp.color.get_b();
        cairo_pattern_add_color_stop_rgba(pattern, 0.0, r, g, b, a);
    }

    for (iter = mygradient.begin(); iter != mygradient.end(); iter++) {
        cp = *iter;
        a = cp.color.get_a();
        r = cp.color.get_r();
        g = cp.color.get_g();
        b = cp.color.get_b();
        cairo_pattern_add_color_stop_rgba(pattern, cp.pos, r, g, b, a);

        if (a != 1.0) {
            cpoints_all_opaque = false;
        }
    }

    if (loop) {
        cp = *(--mygradient.end());
        a = cp.color.get_a();
        r = cp.color.get_r();
        g = cp.color.get_g();
        b = cp.color.get_b();
        cairo_pattern_add_color_stop_rgba(pattern, 1.0, r, g, b, a);
    }

    return cpoints_all_opaque;
}